[PATCH] D63976: Allow clang -Os and -Oz to work with -flto and lld

[Stephen Checkoway via cfe-commits]

> On Jun 29, 2019, at 15:38, Bernhard Rosenkränzer via Phabricator via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
> bero created this revision.
> bero added a reviewer: llvm-commits.
> bero added a project: clang.
> Herald added subscribers: cfe-commits, dexonsmith, inglorion, mehdi_amini.
> 
> Fix clang -Os/-Oz with LTO
> 
> $ clang -Os -fuse-ld=lld -flto test.c
> ld.lld: error: -plugin-opt=Os: number expected, but got 's'
> clang-9: error: linker command failed with exit code 1 (use -v to see invocation)
> $ clang -Oz -fuse-ld=lld -flto test.c
> ld.lld: error: -plugin-opt=Oz: number expected, but got 'z'
> clang-9: error: linker command failed with exit code 1 (use -v to see invocation)
> 
> https://bugs.llvm.org/show_bug.cgi?id=42445
> 
> 
> Repository:
>  rC Clang
> 
> https://reviews.llvm.org/D63976
> 
> Files:
>  llvm-9.0.0-20190629/clang/lib/Driver/ToolChains/CommonArgs.cpp
> 
> 
> Index: llvm-9.0.0-20190629/clang/lib/Driver/ToolChains/CommonArgs.cpp
> ===================================================================
> --- llvm-9.0.0-20190629/clang/lib/Driver/ToolChains/CommonArgs.cpp
> +++ llvm-9.0.0-20190629/clang/lib/Driver/ToolChains/CommonArgs.cpp
> @@ -389,8 +389,11 @@
>     if (A->getOption().matches(options::OPT_O4) ||
>         A->getOption().matches(options::OPT_Ofast))
>       OOpt = "3";
> -    else if (A->getOption().matches(options::OPT_O))
> +    else if (A->getOption().matches(options::OPT_O)) {
>       OOpt = A->getValue();
> +      if(OOpt == "s" || OOpt == "z")
> +        OOpt = "3";
> +    }

Is this going to enable inlining? A user might be quite surprised to find multiple inlined versions of a function when compiled with -Os and especially with -Oz.

>     else if (A->getOption().matches(options::OPT_O0))
>       OOpt = "0";
>     if (!OOpt.empty())
> 
> 
> <D63976.207208.patch>_______________________________________________
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-- 
Stephen Checkoway